我国历史上的私人秘书出现于（）
A.部落联盟昌盛时期
B.夏
C.西周
D.春秋战国
参考答案：D
— What's wrong with her? Look at her ______ eyes.
— Yes, she must have been ______.
A．surprised; surprised
B．surprised; surprising
C．surprising; surprised
D．surprising; surprising
通风机安装工需要了解有关煤矿（）的知识。
A、气体、煤尘爆炸
B、瓦斯、煤尘爆炸
C、瓦斯、粉尘爆炸
D、沼气、煤尘爆炸
